In the case of known machine tools and production machines, such as multi-spindle automatic lathes or rotary tables for example, electric motors, polyphase machines in particular, are arranged on a machine member which is capable of moving in a rotary fashion. In this situation, any drive control facilities and also a power electronics facility, such as line-commutated rectifiers, self-commutated rectifiers or unregulated rectifiers and inverters, for operating the motors are normally located in a control cabinet. In this situation, the power lines are as a rule routed out of the control cabinet in the direction of the motors.
On these machine tools and production machines, in which the power lines are used for connecting the power electronics facility to the machine part which is capable of moving in a rotary fashion, the circumstance in which no “continuous rotation” of the moved machine part can be executed in order to reduce the work piece processing times is to be regarded as disadvantageous. Furthermore, the power lines wear out relatively quickly as a result of the permanent bending and torsional stress. Moreover, replacement of the power lines in the event of a fault is extremely complicated on account of a complex machine design.
As a result, machine tools and production machines having the “continuous rotation” functionality are nowadays being used with increasingly frequency. Such types of machines are thus already known from the prior art. In this situation, the transfer of energy normally takes place by way of collector rings, or inductively, whereby the inductive transfer of energy denotes a considerable additional requirement in terms of power electronics.
Serial bus systems are used for the communication considered in the present case between fixed components, such as a control unit for example, and the rotatable components, such as a drive control facility for example. In this situation, the transfer of data can likewise take place by way of collector rings as in the case of the transfer of energy. In the present case, however, the invention is concerned with a transfer of information by means of light signals. With regard to the devices known from the prior art for transferring light signals between two elements of a machine which are movable relative to one another, glass or plastic bodies are fed with modulated light, whereby the lightwave signals constitute the protocol for the serial communication path.